AP Biology Unit 6 - Gene Expression and Regulation

studied byStudied by 10 people
4.0(1)
learn
LearnA personalized and smart learning plan
exam
Practice TestTake a test on your terms and definitions
spaced repetition
Spaced RepetitionScientifically backed study method
heart puzzle
Matching GameHow quick can you match all your cards?
flashcards
FlashcardsStudy terms and definitions

1 / 63

encourage image

There's no tags or description

Looks like no one added any tags here yet for you.

64 Terms

1

nucleic acids

  • basis for heredity for all life in earth

New cards
2

eukaryotic DNA

  • structured in multiple linear chromosomes contained w/in nucleus

  • each chromosome contains unique set of genes that carry information for making RNA and in turn proteins

  • additional genetic info can be housed outside of chromosome

New cards
3

prokaryotic DNA

  • structured in a single circular chromosome

  • additional genetic info can be housed outside of chromosome

New cards
4

extra-chromosomal DNA

  • additional genetic info can be housed outside of chromosome

  • ex. plasmids, mitochondrial/chloroplastic DNA

New cards
5

plasmids

  • both prokaryotes and eukaryotes can have small, circular, double-stranded DNA molecules (extra-chromosomal)

New cards
6

semiconservative replication

  • the process by which DNA is copied

  • one strand of DNA serves as a template for the second strand to form

  • some enzymes and RNA are involved in this process

New cards
7

helicase

  • enzyme that separates double strands into single strands

  • allows replication machinery access to single strands of DNA

New cards
8

replication fork

  • point where DNA splits into 2 strands

New cards
9

topoisomerase

  • works just in front of replication fork to keep double stranded DNA from supercoiling

  • breaks phosphate backbone, allowing for unwinding and resealing DNA

New cards
10

DNA polymerase III

  • synthesizes new DNA by adding new nucleotides to the 3’ end of DNA

  • because of this, DNA is always synthesized in 5’ to 3’ direction

  • DNA polymerases are capable of proofreading their work so they are able to correct any mistakes made in replication

New cards
11

RNA primers

  • required for DNA polymerases do not initiate synthesis of a single strand of DNA

  • short strands of nucleotides

  • DNA polymerase acts by adding new nucleotides at the end of the RNA primers

  • eventually replaced by DNA polymerase I

New cards
12

DNA polymerase I

  • eventually replaces the RNA primers

New cards
13

leading strand

  • the strand of DNA that is continuously repliacted on

New cards
14

lagging strand

  • “anti-parallel strand”

  • DNA is replicated in short segments called Okazaki fragments

  • RNA primers are attached to sections of DNA strands and DNA polymerase III adds nucleotides in the 5’ to 3’ direction btwn primers

  • DNA ligase seals gaps btwn double stranded fragments on lagging strand

New cards
15

okazagi fragments

  • DNA is replicated in short segments called Okazaki fragments on the lagging strand

New cards
16

DNA ligase

  • seals gaps btwn double stranded fragments on lagging strand

New cards
17

origin of replication

  • circular DNA in most prokaryotes have one specific sequence of DNA that signals where replication begins

    • this sequence is called the origin of replication

  • when DNA replicates, replication bubble forms w/ 2 replication forks @ each end

  • bubble grows until you have 2 copies of DNA

  • in eukaryotes : each chromosome has many origins of replication

    • due to the way lagging strand is formed, some DNA is lost in each round of replication at telomeres

New cards
18

telomeres

  • ends of linear chromosomes

New cards
19

genes

  • stretches of DNA that encode blueprints to make RNA and, in turn, proteins

New cards
20

making proteins 1 : transcription

  • mRNA is formed

  • 2 DNA strands in helix unzip to allow RNA polymerase to make a complementary copy of the gene (mRNA)

New cards
21

mRNA

  • messenger RNA

  • made in 5’ to 3’ direction by reading DNA strand in 3’ to 5’ direction

New cards
22

RNA polymerase

  • synthesizes RNA by following a strand of DNA

New cards
23

pre-mRNA

  • newly transcribed mRNA

  • not yet ready for export from nucleus and translation to protein

New cards
24

posttransational modifications

  • for mRNA to mature

  • addition of 5’ GTP cap

    • important for targeting mRNA for nuclear export, preventing degredation, promoting translation

    • poly(A) tail is also added to 3’ end of mRNA

New cards
25

poly(A) tail

  • string of adenosines that are important for nuclear export, protection from degredation, and translation

New cards
26

introns

  • some parts of sequence that do not translate into proteins

  • must be removed throguh splicing

New cards
27

RNA splicing

  • process where newly-made precusor messenger RNA transcript is transformed into a mature messenger RNA

  • removes all introns and splices exons back together

New cards
28

exons

  • parts of the gene that encodes mature mRNA

  • selectively included or excluded, resulting in several different sequences of proteins from the same gene in an organism

New cards
29

alternative splicing

  • selectively included or excluded, resulting in several different sequences of proteins from the same gene in an organism

New cards
30

making proteins 2 : translation

  • shuttled out of nucleus to cytoplasm for next step

  • proteins are made

  • mRNA enters ribosome where tRNA translates message to make proteins

  • tRNA recognizes mRNA sequences and translates them to amino acid sequences

  • bulk of ribosomes are also made of rRNA and proteins

  • ribosomes bring mRNA and complimentary tRNAs together so protein forms

  • eukaryotes : ribosomes are found both in cytoplasm and on rough endoplasmic reticulum; translation can occur @ either of these sites

  • prokaryotes : translation occurs in cytoplasm

New cards
31

tRNA

  • transfer RNA

  • translate message to make proteins

  • link between mRNA and chain of amino acids

New cards
32

rRNA

  • ribosomal RNA

  • makes up ribosomes

  • exported to cytoplasm ot help translate mRNA information into protein

New cards
33

translation 1 : initiation

  • start codon signals start of translation

  • RNA-amino acid code is universal for all life on Earth

  • same sequence of codons encodes same amino acids for any form of life, providing evidence of a common ancestor

New cards
34

start codon

  • mRNA sequence that signals start of translation

New cards
35

codons

  • groups of three base pairs, the sequence of which encodes either a specific amino acid or start of stop sequence

New cards
36

translation 2 : elongation

  • tRNA read mRNA codon through RNA interactions

  • signals attached amino acid to be transferred to growing protein chain called polypeptide chain

  • mRNA continues to elongate until it reaches stop codon

New cards
37

stop codon

  • signals termination of translation

New cards
38

translation 3 : termination

  • translation is stopped

  • newly formed protein is released

New cards
39

prokaryote translation

  • no nucleus : transcription and translation occur simultaneously

  • have some forms of posttranslational modifications but different than those of eukaryotes

  • no known introns, no alternative splicing

New cards
40

retroviruses

  • viruses made of RNA

  • genetic info from retroviruses is first reverse-transcribed into DNA through reverse transcriptase

  • DNA integrates into the genome of the infected cell through integrate

  • once integrated, virus takes advantage of transcription and translation machinery of cell to replicate new viral progeny

New cards
41

reverse transcriptase

  • enzyme

  • takes single stranded viral RNA molecule and transcribes it into a double stranded DNA

New cards
42

integrase

  • enzyme

  • helps viral DNA to enter into genome of affected cell

New cards
43

transcription factors

  • proteins that regulate transcription of subsets of genes

  • expressed during organism development to help determine which subsets of genes are expressed and what type of cell is ultimately formed

New cards
44

regulatory sequences

  • stretches of DNA that control transcription

  • help modulate expression of genes

  • transcription factors and other gene regulatory proteins identify specific regulatory sequences and use those as a guide to direct which genes are expressed and how much protein is made

New cards
45

promoters

  • sequences where RNA polymerase and transcription factors bind to initiate transcription

New cards
46

enhancers

  • regulatory sequences where proteins bind to increase the likelihood of transcription occuring

  • negative regulatory molecules also exist that decrease transcription

  • ex. silencers

New cards
47

silencers

  • DNA sequences that bind proteins called repressors and block RNA polymerase from binding

New cards
48

operons (called operons in prokaryotes)

  • groups of genes regulated together as a group by a single promotor generating a single mRNA

  • ex. lac operon - contains all proteins for a cell to metabolize lactose

New cards
49

eukaryotic operons

  • gene exp coordinated through expression of transcription factors that regulate many genes in different locations that specify a cell type

New cards
50

epigenetics

  • modifications in gene expression through factors other than alterations to DNA sequence

  • ex. methylation of DNA or alterations to histones that DNA wraps around in cells

  • changes can enhance or reduce gene exp.

New cards
51

mutations

  • alterations in genes or the produces that they make

  • can be negative, neutral, or positive based on the effect they have on the organism

  • emergence of mutations that affect phenotypes —> basis for genetic diversity of a species

  • can be caused by errors in DNA replication or repair, external factors (radiation, exposure to mutagenic chemicals), errors in mitosis or meiosis can change chromosome number

    • whether its a negative or positive effect depends on the environment

New cards
52

missene mutations

  • changes in one single base pair of DNA, causing an amino acid to change from one type to another

New cards
53

nonsense mutations

  • result of a single base pair change that causes a premature stop codon to appear and shortened protein to be produced

New cards
54

insertion mutations

  • caused by the insertion of a short piece of DNA into a genes

New cards
55

deletion mutations

  • occur when one or many base pairs of DNA are deleted

  • can affect single gene or many genes

New cards
56

duplication mutations

  • result of a bit of DNA being copied one or many times

New cards
57

frameshift mutations

  • insertion or deletion of base pairs causes codon frame of a gene to shift so part of the protein downstram of the mutation translates to different amino acids

  • happens whenever there is an insertion or deletion in an exon that is not a multiple of 3 base pairs

New cards
58

errors in meiosis or mitosis

  • cause changes in chromosome number

  • in reproduction, chromosomal mutations can cause new phenotypes to emergy, like sterily

  • can result in developmental limitations, as is the case for individuals affected by Down syndrome

New cards
59

mechanisms for sharing DNA

  • allow for the enhanced survival and reproduction of a species

  • ex. horizontal transfer of DNA in form of plasmids, either throguh uptake of naked DNA or through cell-to-cell transmission

    • uptake of viral DNA —> alters DNA sequence

New cards
60

electrophoresis

  • method used to separate molecules by size na dcharge

  • used to separate DNA, RNA, or protein fragments to help scientists identify what molecules are present

New cards
61

polymerase chain reaction (PCR)

  • used to amplify a single DNA fragment into many identical fragments

  • by selectively amplifying a sequence of DNA, scientists are more easily able to identify it through electrophoresis, sequence it, or transfect it into other cells

New cards
62

bacterial transformation

  • takes advantage of horizontal gene transfer to introduce new DNA to bacteria

  • can be used to produce a protein of interest in large amounts

  • methods have also been established to allow gene transfer in eukaryotes, including humans

New cards
63

horizontal gene transfer

  • movement of genetic information across normal mating barriers, between more or less distantly related organisms

New cards
64

DNA sequencing

  • determines genetic sequence of nucleotides in DNA

  • can be small scale or whole genome sequencing that determines entire genetic code of an organism

New cards
robot